Uniform molding and demolding of structures on highly curved surfaces through conformal contact is a crucial yet often-overlooked aspect of nanoimprint lithography(NIL).This study describes the development of a NIL to...Uniform molding and demolding of structures on highly curved surfaces through conformal contact is a crucial yet often-overlooked aspect of nanoimprint lithography(NIL).This study describes the development of a NIL tool and its integration into a nanopositioning and nanomeasuring machine to achieve high-precision orthogonal molding and demolding for soft ultraviolet-assisted NIL(soft UV-NIL).The process was implemented primarily on the edges of highly curved plano-convex substrates to demonstrate structure uniformity on the edges.High-resolution nanostructures of sub-200-nm lateral dimension and microstructures in the range of tens of microns were imprinted.However,the nanostructures on the edges of the large,curved substrates were difficult to characterize precisely.Therefore,microstructures were used to measure the structure fidelity and were characterized using profilometry,white light interferometry,and confocal laser scanning microscopy.Regardless of the restricted imaging capabilities at high inclinations for high-resolution nanostructures,the scanning electron microscope(SEM)imaging of the structures on top of the lens substrate and at an inclination of 45°was performed.The micro and nanostructures were successfully imprinted on the edges of the plano-convex lens at angles of 45°,60°,and 90°from the center of rotation of the rotating NIL tool.The method enables precise imprinting at high inclinations,thereby presenting a different approach to soft UV-NIL on curved surfaces.展开更多
Illumination with LEDs is of increasing interest in imaging and lithography.In particular,compared to lasers,LEDs are temporally and spatially incoherent,so that speckle effects can be avoided by the application of LE...Illumination with LEDs is of increasing interest in imaging and lithography.In particular,compared to lasers,LEDs are temporally and spatially incoherent,so that speckle effects can be avoided by the application of LEDs.Besides,LED arrays are qualified due to their high optical output power.However,LED arrays have not been widely used for investigating optical effects,e.g.,the Lau effect.In this paper,we propose the application of an LED array for realizing the Lau effect by taking into account the influence of the coherence properties of illumination on the Lau effect.Using spatially incoherent illumination with the LED array or a single LED,triangular distributed Lau fringes can be obtained.We apply the obtained Lau fringes in the optical lithography to produce analog structures.Compared to a single LED,the Lau fringes using the LED array have significantly higher intensities.Hence,the exposure time in the lithography process is largely reduced.展开更多
基金the support by the Deutsche Forschungsgemeinschaft(DFG)in the framework of the Research Training Group Tip and Laser-based 3D-Nanofabrication in extended macroscopic working areas(GRK 2182)at the Technische Universitat Ilmenau,Germany.
文摘Uniform molding and demolding of structures on highly curved surfaces through conformal contact is a crucial yet often-overlooked aspect of nanoimprint lithography(NIL).This study describes the development of a NIL tool and its integration into a nanopositioning and nanomeasuring machine to achieve high-precision orthogonal molding and demolding for soft ultraviolet-assisted NIL(soft UV-NIL).The process was implemented primarily on the edges of highly curved plano-convex substrates to demonstrate structure uniformity on the edges.High-resolution nanostructures of sub-200-nm lateral dimension and microstructures in the range of tens of microns were imprinted.However,the nanostructures on the edges of the large,curved substrates were difficult to characterize precisely.Therefore,microstructures were used to measure the structure fidelity and were characterized using profilometry,white light interferometry,and confocal laser scanning microscopy.Regardless of the restricted imaging capabilities at high inclinations for high-resolution nanostructures,the scanning electron microscope(SEM)imaging of the structures on top of the lens substrate and at an inclination of 45°was performed.The micro and nanostructures were successfully imprinted on the edges of the plano-convex lens at angles of 45°,60°,and 90°from the center of rotation of the rotating NIL tool.The method enables precise imprinting at high inclinations,thereby presenting a different approach to soft UV-NIL on curved surfaces.
基金the support by the Deutsche Forschungsgemeinschaft(DFG)in the framework of Research Training Group“Tip and laser-based 3D-nanofabrication in extended macroscopic working areas”(GRK 2182/1)at the Technische Universitat Ilmenau,Germany.
文摘Illumination with LEDs is of increasing interest in imaging and lithography.In particular,compared to lasers,LEDs are temporally and spatially incoherent,so that speckle effects can be avoided by the application of LEDs.Besides,LED arrays are qualified due to their high optical output power.However,LED arrays have not been widely used for investigating optical effects,e.g.,the Lau effect.In this paper,we propose the application of an LED array for realizing the Lau effect by taking into account the influence of the coherence properties of illumination on the Lau effect.Using spatially incoherent illumination with the LED array or a single LED,triangular distributed Lau fringes can be obtained.We apply the obtained Lau fringes in the optical lithography to produce analog structures.Compared to a single LED,the Lau fringes using the LED array have significantly higher intensities.Hence,the exposure time in the lithography process is largely reduced.
